Microelectronic devices designed with capacitive and enhanced inductive bumps

ABSTRACT

Embodiments of the invention include a microelectronic device that includes a substrate having transistor layers and interconnect layers including conductive layers to form connections to transistor layers. A capacitive bump is disposed on the interconnect layers. The capacitive bump includes a first electrode, a dielectric layer, and a second electrode. In another example, an inductive bump is disposed on the interconnect layers. The inductive bump includes a conductor and a magnetic layer that surrounds the conductor.

FIELD OF THE INVENTION

Embodiments of the present invention relate generally to the manufactureof semiconductor devices. In particular, embodiments of the presentinvention relate to microelectronic devices that are designed withcapacitive and enhanced inductive bumps.

BACKGROUND OF THE INVENTION

Future wireless and wireline communication products are targetingoperation frequencies much higher than the lower GHz range utilizedpresently. For instance 5G (5^(th) generation mobile networks or 5^(th)generation wireless systems) communications are expected to operate at afrequency greater than or equal to 15 GHz. Moreover, the current WiGig(Wireless Gigabit Alliance) products operate around 60 GHz (e.g. 57-66GHz worldwide). Other applications including high performance computing,medical imaging, and sensing utilize wireless communication technologiesin the millimeter wave frequencies (e.g., 24 GHz-300 GHz).

In addition, advanced detection and other high frequency imagingapproaches are being pushed and will be miniaturized to the point wherethese approaches are an integral part of almost any smart device. Athigh frequency ranges, femto Farad (fF) and sub-fF capacitance isrequired in the realization of the mm-wave and sub-Terahertz (sub-THz)circuits. Capacitors on either the die or the package may be susceptibleto process variation or not conveniently located for some matching andfiltering circuits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view of a microelectronic devicehaving capacitive bumps in accordance with one embodiment.

FIGS. 2A-2E illustrate a process for manufacturing a microelectronicdevice having a capacitive bumps in accordance with one embodiment.

FIG. 3 illustrates a cross-sectional view of a microelectronic devicehaving inductive bumps in accordance with one embodiment.

FIG. 4 illustrates a cross-sectional view of a microelectronic devicehaving capacitive bumps that are coupled to a package substrate inaccordance with one embodiment.

FIG. 5 illustrates a cross-sectional view of a microelectronic devicehaving capacitive and inductive bumps that are coupled to a packagesubstrate in accordance with one embodiment.

FIG. 6A illustrates a cross-sectional view of a capacitive bump inaccordance with one embodiment.

FIG. 6B illustrates a simulated capacitance versus frequency for avariable dielectric thickness for capacitive bumps in accordance withone embodiment.

FIG. 7 illustrates a computing device 900 in accordance with oneembodiment.

DETAILED DESCRIPTION OF THE INVENTION

Described herein are microelectronic devices that are designed withcapacitive and enhanced inductive bumps. In the following description,various aspects of the illustrative implementations will be describedusing terms commonly employed by those skilled in the art to convey thesubstance of their work to others skilled in the art. However, it willbe apparent to those skilled in the art that embodiments of the presentinvention may be practiced with only some of the described aspects. Forpurposes of explanation, specific numbers, materials and configurationsare set forth in order to provide a thorough understanding of theillustrative implementations. However, it will be apparent to oneskilled in the art that embodiments of the present invention may bepracticed without the specific details. In other instances, well-knownfeatures are omitted or simplified in order to not obscure theillustrative implementations.

Various operations will be described as multiple discrete operations, inturn, in a manner that is most helpful in understanding embodiments ofthe present invention, however, the order of description should not beconstrued to imply that these operations are necessarily orderdependent. In particular, these operations need not be performed in theorder of presentation.

For high frequency (e.g., 5G, WiGig) wireless applications of millimeter(e.g., 1-10 mm, any mm wave or higher) wave communication systems oreven lower frequency applications, the present design utilizescapacitors integrated in some of the die bumps primarily for highfrequency applications. Another embodiment of the present designenhances the bump inductance by using high permeability material.

The present design modifies the die bump plating and fabricationoperation to include a dielectric layer that makes the bump capacitive.In another embodiment, a fabrication operation is added to the bumpfabrication to make it highly inductive. The present design utilizescapacitive bumps, which are less susceptible to process variations andhave higher qualify factors than on-die metal insulator metal (MIM)capacitors or metal finger capacitors (MFCs).

The combination of capacitive bumps with standard or inductiveconnections (e.g., vias) enable resonant connections (e.g., vias) thatcan act as a stopband filter for certain frequencies while lettingsignals for other frequencies through. The capacitive bump connectionscan be used with on-package inductors to create hybrid high-Q filtersfor millimeter wave and sub-THz circuits and modules. Hybrid in thiscase means some of the components of the filters are on-die while othersare off-die, e.g., on the package substrate. The bump capacitance can bemade using dielectric material in the micron thickness range to enablehigh frequency operation while improving the tolerance. Dielectricthicknesses in the micron thickness range are not effective for planarcapacitors on chip.

In one example, a 5G architecture operates at a high frequency (e.g., atleast 20 GHz, at least 25 GHz, at least 28 GHz, at least 30 GHz, atleast 39 GHz, at least 60 GHz, at least 73 GHz, etc.) and may also haveapproximately 1-50 gigabits per second (Gbps) connections to end points.In another example, the present design operates at lower frequencies(e.g., at least 4 GHz, approximately 4 GHz).

FIG. 1 illustrates a cross-sectional view of a microelectronic devicehaving capacitive bumps in accordance with one embodiment. Themicroelectronic device 100 includes a semiconductor substrate 102 (e.g.,Silicon semiconductor substrate), front end layers 104 for formingdevices (e.g., transistors), and back end layers 106 (e.g., interconnectlayers 106) having conductive layers isolated with dielectric layers forconnecting the devices of the front end layers to conductive bumps(e.g., capacitive bump 160, bump 110, capacitive bump 120, capacitivebump 130). A traditional bump 110 includes an electrode 114 (e.g.,Copper electrode) and an optional solder cap 112. A capacitive bump 120(e.g., metal insulator metal (MIM) capacitor 120) includes electrodes122 and 124 (e.g., Copper electrodes), a dielectric material 123, and anoptional solder cap 125. A capacitive bump 130 (e.g., metal insulatormetal (MIM) capacitor 130) includes electrodes 132 and 134 (e.g., Copperelectrodes), a dielectric material 133, and an optional solder cap 135.The electrode 134 is disposed on passivation material 138. A capacitivebump 160 (e.g., metal insulator metal (MIM) capacitor 160) includeselectrodes 162 and 164 (e.g., Copper electrodes), a dielectric material163, and an optional solder cap 165.

In one example, each electrode 114, 122, 132, and 162 is electricallycoupled to a conductive pad layer of the back end layers 106 to form anelectrical connection with a semiconductor device of the front endlayers 104. The electrodes of the bumps 120 and 130 are thick enough(e.g., approximately at least 200 hundred nanometers, at least onemicron, at least 5 microns, at least 10 microns, etc.) to achieve a highquality factor in comparison to thin metal layers used in the back endlayers 106. The dielectric material 163, 123, and 133 can have athickness with a range of several hundred nanometers to a few microns.The optional solder material (e.g., solder caps) enable connection to asubstrate package or another microelectronic device (e.g., die).

FIGS. 2A-2E illustrate a process for manufacturing a microelectronicdevice having a capacitive bumps in accordance with one embodiment. Themicroelectronic device 200 includes a semiconductor substrate 202 havingfront end layers 204 and back end layers 206 as illustrated in FIG. 2A.Electrodes 210-213 of different sized conductive bumps are formed (e.g.,plated, polished) on the back end layers as illustrated in FIG. 2B.Then, a dielectric material 220-221 is formed on capacitive andnon-ohmic bumps as illustrated in FIG. 2C. Additional electrodes 230-233are formed (e.g., plated) on the bumps as illustrated in FIG. 2D. Then,solder caps 241-244 are optionally formed on the bumps as needed asillustrated in FIG. 2E.

FIG. 3 illustrates a cross-sectional view of a microelectronic devicehaving inductive bumps in accordance with one embodiment. Themicroelectronic device 300 includes a semiconductor substrate 302 (e.g.,Silicon semiconductor substrate), front end layers 304 for formingdevices (e.g., transistors), and back end layers 306 (e.g., interconnectlayers 306) having conductive layers isolated with dielectric layers forconnecting the devices of the front end layers to conductive bumps(e.g., bump 310, inductive bump 350). A traditional bump 310 includes anelectrode 314 (e.g., Copper electrode) and an optional solder cap 312.An inductive bump 350 includes conductor 352 (e.g., Gold conductor,Aluminum conductor, Copper conductor 352), magnetic material 354 and 356(e.g., high permeability magnetic material having permeability of atleast 1.5 to 100), and an optional solder cap 355. The inductive bump350 is achieved by surrounding the standard bump with high permeabilitymagnetic material 354-356. A high level process flow for making theinductive bump includes plating all copper pillars (e.g., conductor352), coating the inductive bumps (e.g., pillars) with magneticmaterial, and applying solder cap to all bumps to enable connection to asubstrate package or another microelectronic device (e.g., die). Themagnetic material of the inductive bumps can be designed for lowerfrequency operation (e.g., 5-200 MHz frequency range).

FIG. 4 illustrates a cross-sectional view of a microelectronic devicehaving capacitive bumps that are coupled to a package substrate inaccordance with one embodiment. The microelectronic device 400 includesa semiconductor substrate 402 (e.g., Silicon semiconductor substrate),front end layers 403 for forming devices (e.g., transistors), back endlayers 404 (e.g., back end layers 404 including on die interconnect 406)having conductive layers isolated with dielectric layers for connectingthe devices of the front end layers to conductive bumps (e.g., bump 420,capacitive bumps 430, 440, and 450). A traditional bump 420 includes anelectrode 414 (e.g., Copper electrode) and an optional solder cap 412. Acapacitive bump 450 (e.g., metal insulator metal (MIM) capacitor 450)includes electrodes 452 and 454 (e.g., Copper electrodes), a dielectricmaterial 453, and an optional solder cap 455. A capacitive bump 430(e.g., metal insulator metal (MIM) capacitor 430) includes electrodes432 and 434 (e.g., Copper electrodes), a dielectric material 433, and anoptional solder cap 435. A capacitive bump 440 (e.g., metal insulatormetal (MIM) capacitor 440) includes electrodes 442 and 444 (e.g., Copperelectrodes), a dielectric material 443, and an optional solder cap 445.

The bumps 420, 430, 440, and 450 are coupled to a package substrate withpads 481-483. For this example, the pad and connection 482 couple bothbumps 420 and 450 to the package substrate 480 to form a resonator 490by connecting bumps of different types.

FIG. 5 illustrates a cross-sectional view of a microelectronic devicehaving capacitive and inductive bumps that are coupled to a packagesubstrate in accordance with one embodiment. The microelectronic device500 includes a semiconductor substrate 502 (e.g., Silicon semiconductorsubstrate), front end layers 503 for forming devices (e.g.,transistors), back end layers 504 (e.g., back end layers 504 includingon die interconnect 506) having conductive layers isolated withdielectric layers for connecting the devices of the front end layers toconductive bumps (e.g., bump 520, capacitive bump 550, inductive bumps530 and 540). A traditional bump 520 includes an electrode 514 (e.g.,Copper electrode) and an optional solder cap 512. A capacitive bump 550(e.g., metal insulator metal (MIM) capacitor 550) includes electrodes552 and 554 (e.g., Copper electrodes), a dielectric material 553, and anoptional solder cap 555. An inductive bump 530 includes conductor 532(e.g., Copper conductors), magnetic material 533-534, and an optionalsolder cap 535. An inductive bump 540 includes conductor 542 (e.g.,Copper conductors), magnetic material 543-544, and an optional soldercap 545.

The bumps 520, 530, 540, and 550 are coupled to a package substrate withpads 581-583. For this example, the pad and connection 582 couple bothbumps 530 and 550 to the package substrate 580 to form a resonator 590by connecting bumps of different types to each other.

FIG. 6A illustrates a cross-sectional view of a capacitive bump inaccordance with one embodiment. A width of a capacitive bump 600 isshown along an x-axis and a thickness of the bump 600 is shown along avertical z-axis. The bump 600 includes a first electrode 610, adielectric material 620, and a second electrode 630.

FIG. 6B illustrates a simulated capacitance versus frequency for avariable dielectric thickness (td) for capacitive bumps in accordancewith one embodiment. A capacitance in femtoFarads (fF) is plotted on avertical axis and frequency in GHz is plotted on a horizontal axis. Thedielectric thickness (td) varies from 0.5microns to 4.5 microns fordifferent lines to obtain a capacitance of approximately 500 fF to 25fF. In this example, the capacitive bumps have a self-resonance above200 GHz (e.g., 300-400 GHz, 600-700 GHz).

Capacitive bumps can be utilized for RF and high speed signalingapplications while inductive bumps can be utilized for power delivery.

It will be appreciated that, in a system on a chip embodiment, the diemay include a processor, memory, communications circuitry and the like.Though a single die is illustrated, there may be none, one or severaldies included in the same region of the wafer.

In one embodiment, the microelectronic device may be a crystallinesubstrate formed using a bulk silicon or a silicon-on-insulatorsubstructure. In other implementations, the microelectronics device maybe formed using alternate materials, which may or may not be combinedwith silicon, that include but are not limited to germanium, indiumantimonide, lead telluride, indium arsenide, indium phosphide, galliumarsenide, indium gallium arsenide, gallium antimonide, or othercombinations of group III-V or group IV materials. Although a fewexamples of materials from which the substrate may be formed aredescribed here, any material that may serve as a foundation upon which asemiconductor device may be built falls within the scope of embodimentsof the present invention.

FIG. 7 illustrates a computing device 900 in accordance with oneembodiment. The computing device 900 houses a board 902. The board(e.g., motherboard, printed circuit board, etc.) may include a number ofcomponents, including but not limited to at least one processor 904 andat least one communication chip 906. The at least one processor 904 isphysically and electrically coupled to the board 902. In someimplementations, the at least one communication chip 906 is alsophysically and electrically coupled to the board 902. In furtherimplementations, the communication chip 906 is part of the processor904. In one example, the communication chip 906 (e.g., microelectronicdevice 100, 200, 300, 400, 500, etc.) includes an antenna unit 920.

Depending on its applications, computing device 900 may include othercomponents that may or may not be physically and electrically coupled tothe board 902. These other components include, but are not limited to,volatile memory (e.g., DRAM 910, 911), non-volatile memory (e.g., ROM912), flash memory, a graphics processor 916, a digital signalprocessor, a crypto processor, a chipset 914, an antenna unit 920, adisplay, a touchscreen display 930, a touchscreen controller 922, abattery 932, an audio codec, a video codec, a power amplifier 915, aglobal positioning system (GPS) device 926, a compass 924, a gyroscope,a speaker, a camera 950, and a mass storage device (such as hard diskdrive, compact disk (CD), digital versatile disk (DVD), and so forth).

The communication chip 906 enables wireless communications for thetransfer of data to and from the computing device 900. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication chip 906 may implement anyof a number of wireless standards or protocols, including but notlimited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family),WiGig, IEEE 802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+,HSUPA+, EDGE, GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivativesthereof, as well as any other wireless protocols that are designated as3G, 4G, 5G, and beyond. The computing device 900 may include a pluralityof communication chips 906. For instance, a first communication chip 906may be dedicated to shorter range wireless communications such as Wi-Fi,WiGig, and Bluetooth and a second communication chip 906 may bededicated to longer range wireless communications such as GPS, EDGE,GPRS, CDMA, WiMAX, LTE, Ev-DO, 5G, and others.

The at least one processor 904 of the computing device 900 includes anintegrated circuit die packaged within the at least one processor 904.In some embodiments of the invention, the processor package includes oneor more devices, such as microelectronic devices (e.g., microelectronicdevice 100, 200, 300, 400, 500, etc.) in accordance with implementationsof embodiments of the invention. The term “processor” may refer to anydevice or portion of a device that processes electronic data fromregisters and/or memory to transform that electronic data into otherelectronic data that may be stored in registers and/or memory.

The communication chip 906 also includes an integrated circuit diepackaged within the communication chip 906. In accordance with anotherimplementation of embodiments of the invention, the communication chippackage includes one or more microelectronic devices (e.g.,microelectronic device 100, 200, 300, 400, 500, etc.).

The following examples pertain to further embodiments. Example 1 is amicroelectronic device that includes a substrate having transistorlayers and interconnect layers including conductive layers to formconnections to transistor layers and a capacitive bump disposed on theinterconnect layers. The capacitive bump includes a first electrode, adielectric layer, and a second electrode.

In example 2, the subject matter of example 1 can optionally include thecapacitive bump further comprising a solder cap that contacts the secondelectrode to enable electrical connection to a package substrate havingan inductor to create hybrid high quality filters for millimeter wavefrequency circuits.

In example 3, the subject matter of any of examples 1-2 can optionallyinclude the first electrode being coupled to a conductive layer of theinterconnect layers.

In example 4, the subject matter of any of examples 1-3 can optionallyinclude the dielectric layer having a thickness range of 0.05 (50nanometer) to 10 microns.

In example 5, the subject matter of any of examples 1-4 can optionallyinclude the capacitive bump vinga capacitance of 10 femto Farads to 1000femto Farads.

In example 6, the subject matter of any of examples 1-5 can optionallyinclude the dielectric layer surrounding the first electrode and thesecond electrode surrounding the dielectric layer.

In example 7, the subject matter of any of examples 1-7 can optionallyinclude a passivation layer formed on the interconnect layers. Thedielectric layer and the first electrode are formed within an opening ofthe passivation layer and the second electrode is disposed on thepassivation layer.

Example 8 is a microelectronic device comprising a substrate havingtransistor layers and interconnect layers including conductive layers toform connections to transistor layers and an inductive bump disposed onthe interconnect layers. The inductive bump includes a conductor and amagnetic layer that surrounds the conductor.

In example 9, the subject matter of example 8 can optionally include theinductive bump further comprising a solder cap that contacts theconductor to enable electrical connection to a package substrate oranother microelectronic device.

In example 10, the subject matter of any of examples 8-9 can optionallyinclude the conductor being coupled to a conductive layer of theinterconnect layers.

In example 11, the subject matter of any of examples 8-10 can optionallyinclude the magnetic layer having a thickness range of 0.05 to 10microns.

In example 12, the subject matter of any of examples 8-11 can optionallyinclude a bump disposed on the interconnect layers. The bump includes anelectrode and a solder cap.

In example 13, the subject matter of any of examples 8-12 can optionallyinclude the inductive bump providing power delivery for devices of thetransistor layers.

Example 14 is a computing device comprising at least one processor toprocess data and a communication module or chip coupled to the at leastone processor. The communication module or chip comprises asemiconductor substrate having transistor layers and interconnect layersincluding conductive layers to form connections to transistor layers anda capacitive bump disposed on the interconnect layers. The capacitivebump includes a first electrode, a dielectric layer, and a secondelectrode.

In example 15, the subject matter of example 14 can optionally includethe communication module or chip further comprising a package substrateand the capacitive bump further comprising a solder cap that contactsthe second electrode to enable electrical connection to the packagesubstrate having an inductor to create hybrid high quality filters formillimeter wave and sub-THz frequency circuits.

In example 16, the subject matter of any of examples 14-15 canoptionally include the first electrode being coupled to a conductivelayer of the interconnect layers.

In example 17, the subject matter of any of examples 14-16 canoptionally include the dielectric layer having a thickness range of 0.05to 10 microns.

In example 18, the subject matter of any of examples 14-17 canoptionally include the capacitive bump having a capacitance of 10 femtoFarads to 1000 femto Farads.

In example 19, the subject matter of any of examples 14-18 canoptionally include the dielectric layer surrounding the first electrodeand the second electrode surrounding the dielectric layer.

In example 20, the subject matter of any of examples 14-19 canoptionally include a passivation layer formed on the interconnectlayers. The dielectric layer and the first electrode are formed withinan opening of the passivation layer and the second electrode is disposedon the passivation layer.

In example 21, the subject matter of any of examples 14-20 canoptionally include a bump disposed on the interconnect layers. The bumpincludes an electrode and a solder cap with the bump being coupled tothe capacitive bump with a conductive layer of the interconnect layersto form a resonator.

What is claimed is:
 1. A microelectronic device comprising: a substratehaving transistor layers and interconnect layers including conductivelayers to form connections to transistor layers; and a capacitive bumpdisposed on the interconnect layers, the capacitive bump includes afirst electrode, a dielectric layer, and a second electrode.
 2. Themicroelectronic device of claim 1, wherein the capacitive bump furthercomprising a solder cap that contacts the second electrode to enableelectrical connection to a package substrate having an inductor tocreate hybrid high quality filters for millimeter wave frequencycircuits.
 3. The microelectronic device of claim 1, wherein the firstelectrode is coupled to a conductive layer of the interconnect layers.4. The microelectronic device of claim 1, wherein the dielectric layerhas a thickness range of 0.05 to 10 microns.
 5. The microelectronicdevice of claim 4, wherein the capacitive bump has a capacitance of 10femto Farads to 1000 femto Farads.
 6. The microelectronic device ofclaim 1, wherein the dielectric layer surrounds the first electrode andthe second electrode surrounds the dielectric layer.
 7. Themicroelectronic device of claim 6, further comprising: a passivationlayer formed on the interconnect layers, wherein the dielectric layerand the first electrode are formed within an opening of the passivationlayer and the second electrode is disposed on the passivation layer. 8.A microelectronic device comprising: a substrate having transistorlayers and interconnect layers including conductive layers to formconnections to transistor layers; and an inductive bump disposed on theinterconnect layers, the inductive bump includes a conductor and amagnetic layer that surrounds the conductor.
 9. The microelectronicdevice of claim 8, wherein the inductive bump further comprising asolder cap that contacts the conductor to enable electrical connectionto a package substrate or another microelectronic device.
 10. Themicroelectronic device of claim 8, wherein the conductor is coupled to aconductive layer of the interconnect layers.
 11. The microelectronicdevice of claim 8, wherein the magnetic layer has a thickness range of0.05 to 10 microns.
 12. The microelectronic device of claim 8, furthercomprising: a bump disposed on the interconnect layers, the bumpincluding an electrode and a solder cap.
 13. The microelectronic deviceof claim 8, wherein the inductive bump provides power delivery fordevices of the transistor layers.
 14. A computing device comprising: atleast one processor to process data; and a communication module or chipcoupled to the at least one processor, the communication module or chipcomprises, a semiconductor substrate having transistor layers andinterconnect layers including conductive layers to form connections totransistor layers and a capacitive bump disposed on the interconnectlayers, the capacitive bump includes a first electrode, a dielectriclayer, and a second electrode.
 15. The computing device of claim 14,wherein the communication module or chip further comprises a packagesubstrate and the capacitive bump further comprising a solder cap thatcontacts the second electrode to enable electrical connection to thepackage substrate having an inductor to create hybrid high qualityfilters for millimeter wave and sub-THz frequency circuits.
 16. Thecomputing device of claim 14, wherein the first electrode is coupled toa conductive layer of the interconnect layers.
 17. The computing deviceof claim 14, wherein the dielectric layer has a thickness range of
 0. 05to 10 microns.
 18. The computing device of claim 17, wherein thecapacitive bump has a capacitance of 10 femto Farads to 1000 femtoFarads.
 19. The computing device of claim 14, wherein the dielectriclayer surrounds the first electrode and the second electrode surroundsthe dielectric layer.
 20. The computing device of claim 19, furthercomprising: a passivation layer formed on the interconnect layers,wherein the dielectric layer and the first electrode are formed withinan opening of the passivation layer and the second electrode is disposedon the passivation layer.
 21. The computing device of claim 14, furthercomprising: a bump disposed on the interconnect layers, the bumpincluding an electrode and a solder cap with the bump being coupled tothe capacitive bump with a conductive layer of the interconnect layersto form a resonator.